complexity & change in environment, biomedicine & society

Interpreting the Tucson massacre and the relevance of epidemiological thinking

In advising on the most effective measures to be taken to improve the health of a population, epidemiologists may focus on different determinants of the disease than a doctor would when faced with sick or high-risk individuals. This contrast is evident in interpretations of Jared Loughner’s shooting rampage in Tucson—do we focus on Loughner as a deranged individual and consider how we can catch such people before they hurt others or, thinking like a social epidemiologist, do we push for changes in the social conditions that exacerbate damage when deranged individuals arise (e.g., by restricting availability of automatic weapons)?

Geoffrey Rose is well known in social epidemiology for promoting the population health focus (Rose 1985), but this is not universally accepted by healthcare practitioners and policy makers. Road accidents and alcohol consumption may be a good illustration of Rose’s argument. Most of us know of times when we’ve been able to get home safely after we’ve drunk too much “risk factor,” but we also know that a substantial fraction of people in accidents have high alcohol levels. We also sense that some people are more susceptible to having their judgement and reaction times impaired by alcohol so we could imagine doing further epidemiological and biological research to develop multivariable risk factor formulas. Would a more refined knowledge of riskiness help us prioritize our risk-prevention efforts, or would that pale into insignificance relative to drink-don’t-drive efforts? Rose would push for the latter. In the same spirit, he observed that investigating genes that might confer some resistance to lung cancer among smokers—we all know of someone who smoked heavily but lived into their 80s—wouldn’t be a high priority in a society that has eliminated smoking.

In the Loughner case, one Rosean approach would be to restrict availability of automatic weapons. Another would be to promote reduction in rhetoric of individuals having to arm themselves against the tyrannies of the government. Another would be to improve mental health funding so that help would be given to more distressed individuals (even if we had no way to determine if their distress was leading them towards violence). Of course, any given Rosean measure might not be straightforward to institute (e.g., vaccination of girls for HPV is resisted by some on the grounds that it is a promiscuity-promoting measure). Moreover, it may turn out that the Rosean measure does not have the expected effect (e.g., abstinence-only sex education has been shown in some studies not to reduce rates of STDs) and has to be rethought.

Interestingly, right-wing commentators, wishing to resist any points being scored for gun control and anti-vitriol have not simply focussed on Loughner as a deranged individual who, as an individual, is responsible for his own actions. Some have joined in discussion of the idea that mental health services needed to be better. Are they Rosean? There has been ambiguity about whether the improvement is to improve the mental health care for society as a whole or just to detect and “treat” the high-risk individuals.